get data from T

Question

User-1045082127 posted

hi

list of data is send to the bellow fuction:

public static DataTable SetPropertyToDataTable<T>(T dataList,Type _class) where T : class
        {
            Dictionary<string, object> columns = new Dictionary<string, object>();

            var data = dataList as T[];
            var properties =_class.GetProperties(); 

           /* foreach (var item in T)
                foreach (var property in properties)
                {
                    var name = property.Name;
                    var value = property.GetValue(item, null);

                    if(!columns.ContainsKey(name))
                        columns.Add(name, value);
                }*/

            return ImportPropertyAndValues(columns); 
        }

bu when i trace a data value  it contain null. why?

Answer 1

User303363814 posted

The signature of SetPropertyToDataTable tells us that the type of dataList is T.

The 'as' operator says "if dataList is of type T[] then return a value whose type is T[], otherwise return null".

datalist is not if type T[] so the 'as' operator returns null.  It is impossible for something to be of a certain type and also be an array of that same type at the same time.